I am trying to build Qt 6.2.4 from source on Windows 10. I run into the following WARNINGs when configuring.
WARNING: QDoc will not be compiled, probably because libclang could not be located. This means that you cannot build the Qt documentation.
Either set CMAKE_PREFIX_PATH or LLVM_INSTALL_DIR to the location of your llvm installation.
On Linux systems, you may be able to install libclang by installing the libclang-dev or libclang-devel package, depending on your distribution.
On macOS, you can use Homebrew's llvm package.
You will also need to set the FEATURE_clang CMake variable to ON to re-evaluate this check.
WARNING: Clang-based lupdate parser will not be available. LLVM and Clang C++ libraries have not been found.
You will need to set the FEATURE_clangcpp CMake variable to ON to re-evaluate this check.
I have set the LLVM_INSTALL_DIR to the top-level directory of the pre-built libclang on Qt's download site (https://download.qt.io/development_releases/prebuilt/libclang/). In particular, I downloaded the 16.0.2 for windows. I deleted my build directory and configured again. Despite my doing this, it still gives me the WARNINGs. Does someone know what is going on and can give me advice?
It looks like I was not actually setting the LLVM_INSTALL_DIR. I tried to use -D when invoking the configure.bat, instead of using -D with a call to cmake. Calling cmake with the -DLLVM_INSTALL_DIR=/path/to/llvm seemed to actually set the LLVM_INSTALL_DIR.